1. Field of the Invention
An aspect of the present invention relates to an image printing apparatus and a white line compensation method therefor, and more particularly, to an image printing apparatus and a white line compensation method therefor that compensates for white lines produced at the rear portion of a sheet of recording paper when the sheet comes out of a feeding roller.
2. Description of the Related Art
In general, a facsimile machine, a printer, a multi-function machine that comprises multiple functions of a facsimile machine and a printer in one device, or other similar units are manufactured to have a printing function in common, and thus, are equipped with an image printing apparatus to complete a printing function.
Such an image printing apparatus is classified as an inkjet printer or a laser printer based on the printing method of a printing engine.
The inkjet printer has an ink cartridge in which plural nozzles are formed to fire ink, and an ink cartridge driving circuit to drive the ink cartridge in order to form an image on a recording sheet of paper in response to a printing command.
FIG. 1 is a cross-sectioned view schematically showing a conventional inkjet printer.
As shown in FIG. 1, an inkjet printer includes: a pickup roller 120 to pick up recording sheets of paper P loaded in a paper supply cassette 110; a paper feeding part 130 disposed at a predetermined interval to feed a sheet of paper P picked up by the pickup roller 120; a printing part to carry out printing operations; and a paper discharge part 140 to externally discharge a printing-completed recording sheet of paper P.
According to a printing process of the inkjet printer structured as above, a recording sheet of paper P loaded in the paper supply cassette 110 is picked up by the pickup roller 120. The picked-up sheet of paper P is placed in a printing area along a sheet feeding path 100 by the paper feeding part 130. If the sheet of paper P is fed into a printing area, the ink cartridge 150 fires ink on the sheet of paper P fed and forwards the sheet of paper P to carry out the printing job, reciprocating the printer head (not shown) to the left and right.
Consequently, the sheet of paper P on which an image is printed by the ink cartridge 150 is externally discharged along a paper discharge direction by the paper discharge part 140. As a result, a white line is produced due to a backlash phenomenon of a feeding roller 130a at the time the feeding sheet of paper P goes out of the feeding roller 130a and the friction roller 130b of the paper feeding part 130 disposed at a position where the feeding sheet of paper P enters the printing area.
That is, as shown in FIG. 1, in case the rear portion of the sheet of paper P moves from position a to position b, in other words, during the time the sheet of paper P moves out from between the feeding roller 130a and the friction roller 130b, the sheet of paper P is overfed as much as the sheet of paper P is fed by the paper feeding part 130 and the paper discharge part 140. Accordingly, a problem occurs since a white line is produced as, denoted A in FIG. 2, on the rear portion of the sheet of paper P, resulting in deterioration of the printing quality.